Recently, various technologies and methods for coding digital audio signal have been developing, and products related thereto are also being manufactured. Also, there have been developed methods in which audio signals having multi-channels are encoded using a psycho-acoustic model.
The psycho-acoustic model is a method to efficiently reduce amount of data as signals, which are not necessary in an encoding process, are removed, using a principle of human being's sound recognition manner. For example, human ears cannot recognize quiet sound immediately after loud sound, and also can hear only sound whose frequency is between 20˜20,000 Hz.
Although the above conventional technologies and methods have been developed, there is no method known for processing an audio signal to generate a pseudo-surround signal from audio bitstream including spatial information.